The proposed work is partly an extension of work done on recognition, recall, and short-term memory during the last few years, and partly an extension of this work to related problems concerning the structure and organization of long-term memory and information retrieval from long-term memory. Both theoretical and empirical work is proposed in an attempt to gain some understanding of how memory is organized and how information is retrieved. At this stage, the theoretical endeavor consists of some speculations concerning how memory conceivably could be organized, given the constraints posed by the requirements of economy of storage and linguistic relevance. It is hoped that these ideas will eventually lead to the construction of a testable model of memory structure, in interaction with empirical investigations designed to provide some insight into how memory is in fact organized and how it is searched. Some of these studies employ reaction time techniques to explore search processes, while others vary the structural complexity of material in an attempt to determine precisely which sources of complexity significantly affect information processing and retention. While venturing into a new and uncharted research area with the studies mentioned above, I also plan to continue my work on recognition, free recall, and short-term memory. Further work is planned concerning the two-process theory of recognition and recall proposed earlier. Other experiments deal with the general problem of how what the subject does at the time of study (his encoding activities) affects performance at the time of test. This will be investigated in the context of recognition learning (spacing effects, false recognitions), free recall (cueing, part-list recall), and short-term memory (non-acoustic coding in primary memory, various types of cognitive processing during encoding).